1. Technical Field
The present invention relates in general to fluid level indicators. More particularly, but without restriction to the particular embodiment and/or use which is shown and described for purposes of illustration, the present invention relates to fluid level indicators that compensate for the fluid temperature.
2. Discussion
In a conventional automobile, the fluid level of the transmission and engine needs to be closely monitored. High or low fluid levels could have a detrimental effect on the performance and longevity of the vehicle. Typically, a vehicle will include a number of fluid level indicators, commonly referred to as dipsticks. Each dipstick is disposed so that one end thereof enters a reservoir in either the engine or transmission. A dipstick can easily be removed by its other end and used to measure the level of oil therein. The fluid level of the engine or transmission is indicative of the amount of oil, defined by height, that clings to the dipstick.
Typically, a dipstick has a plurality of marking to set desired operating levels or ranges. In most vehicles, a dipstick will have a high and a low marking. An oil level between the high and low marking is desired for optimal performance of the engine. Unfortunately, the volume of oil and other similar fluids is generally dependent on temperature. As an engine or a transmission is operating, a tremendous amount of heat is produced, some of which is transferred to the oil system. As the temperature of the fluid rises, the level of fluid in the reservoir rises. This causes a traditional fluid level indicator to read a higher value. This leads to a discrepancy of fluid level as read by a dipstick depending on the temperature of the fluid.
Many automotive manufacturers have provided instructions for checking fluid levels via a dipstick. Such instructions have included that oil should only be checked when the vehicle has been inoperable for a certain amount of time, or that oil should only be checked when the vehicle is operating. These conditions are postulated in an attempt to estimate fluid temperature. However, this is not always convenient, and furthermore, it is never truly known what temperature the fluid is at even with the aforementioned instructions.
There is, therefore, a need to provide a fluid level indicator that properly describes the desired fluid level dependent on temperature. There is also a need to provide a fluid level indicator that can be used to obtain an accurate reading independent of the operating state and history of the vehicle.